AA:EPA ratio optimal range and reference range
Compiled by Alina Radu, founder of Sera, from the published sources below · Last reviewed November 9, 2026
Sera's bands for AA:EPA ratio:
- Optimal 1 – 3 ratio; sufficient 1 – 6 ratio; out of range below 1 or above 6 ratio.
Evidence grade: Functional / longevity target. A narrower target in common use in functional, integrative, preventive and longevity practice. It is not a universally validated diagnostic range.
At Sera's last range review a change to this band was proposed and held, because the evidence for it was thin, so the band is unchanged. The note below says where it matches published intervals and where it does not.
All units
| Unit | Optimal | Sufficient | Out of range |
|---|---|---|---|
| ratio | 1 – 3 | 1 – 6 | below 1 or above 6 |
What the evidence says
Functional-medicine consensus supports 1 to 3:1 as the anti-inflammatory target. The mechanism is sound — the two families compete for the same desaturase and elongase enzymes, so the balance matters more than either intake alone — but outcome data are considerably less robust than for the Omega-3 Index. This is the eicosanoid ratio, arachidonic acid against EPA; the Total Omega-6:Omega-3 Ratio is the dietary-pattern version and runs several times higher in the same person. No published source states 1 to 3 or 6 for the red cell AA:EPA ratio. Dividing published cohort means gives about 14 to 26 in most Western populations and about 6 in Japan, so the average Western result reads Out of range here while reading Sufficient on the Omega-3 Index. Read this ratio as a functional target and the Index as the better-evidenced measure.
Sources
- MDX_Report_Omega3_ENG.pdf (laboratory sample report for a dried blood spot omega-3 test; the exact report title could not be read from the file) — Mosaic Diagnostics (formerly Great Plains Laboratory); the report refers readers to omegaquant.com for its references, 2017 · Functional-medicine referenceLaboratory report table derived from about 8,900 dried blood samples. AA:EPA 2.5 to 11 is desirable (matching an Omega-3 Index of 8 to 12%), 11 to 25 intermediate (Index 4 to 8%), over 25 undesirable (Index below 4%), below 2.5 elevated. Sera's 1 to 3 and 6 do not match. Dried blood spot, not washed red cells, and a commercial report, not a guideline.
- Red Blood Cell Fatty Acid Patterns from 7 countries: Focus on the Omega-3 Index — Schuchardt JP, Cerrato M, Ceseri M, et al. — Prostaglandins, Leukotrienes and Essential Fatty Acids, 2022 · Peer-reviewed publicationMean red cell arachidonic acid was 14 to 17% in the Western cohorts and EPA 0.43 to 1.06%, which puts the average AA:EPA at roughly 14 to 26 in most of them (39 in one); in Japan, Korea and Alaska (EPA 1.9 to 2.2%, AA about 12%) it is about 6. The ratio itself is not reported; these are divisions of the published means.
- The importance of the omega-6/omega-3 fatty acid ratio in cardiovascular disease and other chronic diseases — Simopoulos AP — Experimental Biology and Medicine, 2008 · Peer-reviewed publicationArgues that the two families compete for the same desaturase and elongase enzymes, so the balance between them matters and not the absolute intake of either. Sets out the low single-figure ratio widely used as a functional target against the 15:1 or higher typical of Western diets. The mechanism is well described; the specific target figure is consensus rather than an outcome-validated threshold.
What Omega-6:Omega-3 Ratio (AA:EPA) measures
The balance between arachidonic acid, an omega-6 fat, and EPA, an omega-3 fat. Two specific fatty acids, not every omega-6 against every omega-3 — that broader measure is the Total Omega-6:Omega-3 Ratio.
A ratio below 3:1 is ideal. A high ratio above 10:1 encourages long-term inflammation. Read it as an exploratory index rather than a diagnostic test — laboratories differ in which fatty acids they sum into each side, so the same blood can give different ratios.